We will pursue the structural characterization of the protein and other non-carbohydrate components to which glycogen is covalently bound in liver and muscle and determine the nature of the linkages between the glycogen and these non-carbohydrate components. The mode of biosynthesis of the linkages will be elucidated, and the sites of occurrence of the non-carbohydrate components in the cells of liver and muscle. We will study the incorporation into glycogen of glucose and of sugar phosphates based on glucose and other monosaccharides, as this process occurs in the frog oocyte. We are especially interested in extending our discovery that glucose 1,6-diphosphate can be incorporated into glycogen and of the powerful inhibitory effect that this compound has on the incorporation of other precursors such as glucose. Our observations, confirming the work of Maley et al., that glucosamine can substitute for glucose as a monosaccharide unit of glycogen, has been extended to include 2-deoxyglucose and xylose, possibly also galactose, as sugars that can also be incorporated into the macromolecule. We will study further the enzymic mechanisms for the insertion and removal of these sugars into and from glycogen and their effects on glycogen metabolism and structure.